A common technique used by dishonest persons to prepare counterfeit checks is to place a piece of paper between the printer ribbon and a blank check in a check printer. The printer is then allowed to enter the amount and the name of the payee onto the piece of paper. The date, signature and other authenticating data is printed on the check. The partially filled out check then exits the printer in the normal manner. The dishonest person can then take the check to a typewriter or to another check printer and fill out the check thereby preparing an authentic appearing counterfeit.
The guard of the present invention protects the blank checks by closing the gap between the printer ink ribbon cartridge and check. The leading edge of the guard is configured to apply a thin line of pressure to the face of the check which is too strong to be overcome by a piece of paper or a thin metal shim. The edges of the guard are tapered inwardly toward the center to prevent a paper or metal shim from being entered from the side.